Field of the Invention
The present invention relates generally to safety systems and arrangements and, in particular, to a line retraction device, such as a fall arrest or controlled descent device, including self-retracting lanyards and the like, which may be used in connection with a harness to protect the wearer from a sudden, accelerated fall arrest event, as well as a line retraction device having a damper assembly.
Description of the Related Art
A line retraction device may be used in a variety of situations and applications. For example, one type of line retraction device is in the form of a lanyard, such as a self; retracting lanyard (SRL), which are commonly used for fall protection in industrial environments, as well as in connection with recreational activities. Self-retracting lanyards have numerous industrial end uses, including, but not limited to, construction, manufacturing, hazardous materials/remediation, asbestos abatement, spray painting, sand blasting, welding, mining, numerous oil and gas industry applications, electric and utility, nuclear energy, paper and pulp, sanding, grinding, stage rigging, roofing, scaffolding, telecommunications, automotive repair and assembly, warehousing, and railroading.
SRLs frequently include a housing that includes a rotatable drum or hub around which a line, typically made of webbing, cable, rope, and/or synthetic material is wound. The hub rotates to unwind (or “payout”) the line from its housing when a certain level of tension is purposefully applied. When that degree of tension is reduced or released, the hub can slowly rotate in a reverse direction causing the line to retract or rewind about itself in a desired manner. Certain housings further include a braking mechanism or assembly for resisting hub rotation when an inelastic line (e.g., a steel cable) unwinds too rapidly, i.e., faster than its predetermined maximum velocity for normal payout. A sudden line payout is an indication that the lanyard wearer/user has experienced a fall that needs to be stopped or arrested.
During an unintentional, accidental fall, an engagement and braking arrangement in the housing of the SRL engages, which prevents the SRL wearer from falling too far. In addition, SRLs typically connect at one end to an anchorage point, often on the support structure at or near where a user is performing certain assigned tasks. The line from the SRL housing is clamped (or otherwise attached) to a harness worn by the user. The maximum allowable stopping forces and distances are defined by known industry standards. The stopping force provided by a brake is inversely proportional to the stopping distance, i.e., the higher the force, the shorter the distance, and vice versa. As a result, the force cannot exceed the maximum allowed by standards, and yet it must also be large enough so that the extension distance does not exceed the maximum, also regulated by these standards.
The drum of the SRL is biased to retract the line back into the housing of the SRL. As noted above, the line will payout from the drum as the user walks away from the SRL and will also retract back into the housing as the user walks toward the SRL. When a user disconnects the line from their harness and releases the line, “freewheeling” can occur, which is the unrestrained retraction of the line back into the housing of the SRL. When the end of the line reaches the SRL, an end connector on the line can impact the housing of the SRL and damage the housing, the end connector, and/or the internal components of the SRL. Such an impact may also jam the SRL requiring the repair of the SRL and, in some circumstances, injure the user. The issues caused by the impact of the end connection against the housing may create a dangerous condition where the SRL may not function properly the next time it is used. Proper line retraction is typically controlled by the user either directly by hand or indirectly with a tag line secured to the main line of the SRL.